Examples

Complete curl examples for the EenFactuurMaken.nl REST API. Create, check, issue and email an invoice, mark it paid, credit it, send reminders and fetch VAT figures.

All examples use curl and jq. First put your key in a variable:

bash

export EENFACTUURMAKEN_API_KEY=efm_your_key
export API=https://eenfactuurmaken.nl/api/v1

Create and send an invoice

1. Create a draft

With a new customer included (it's created at the same time). Use customerId for an existing customer.

bash

INVOICE=$(curl -s -X POST "$API/invoices" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "customer": {
      "type": "business",
      "name": "Bakkerij De Gouden Korst",
      "email": "administratie@goudenkorst.nl",
      "addressLine1": "Dorpsstraat 1",
      "postalCode": "1234 AB",
      "city": "Utrecht",
      "country": "NL",
      "kvkNumber": "12345678"
    },
    "reference": "Website 2026",
    "lines": [
      { "description": "Web design", "quantity": "12", "unit": "HUR", "unitPriceCents": 8500, "vatRate": "21" },
      { "description": "Hosting (year)", "quantity": "1", "unitPriceCents": 12000, "vatRate": "21" }
    ]
  }' | jq -r .id)
echo $INVOICE

Dates, payment term, language and VAT treatment come from the customer and your settings. The response is the complete invoice object, with totalCents (here 137940) and compliance.

2. Check it

bash

curl -s "$API/invoices/$INVOICE/compliance" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq '.[] | select(.level=="error")'

No output means: no errors. See Invoice checks for all codes.

3. Issue it

bash

curl -s -X POST "$API/invoices/$INVOICE/issue" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{}' | jq '{number, status, publicUrl}'

You can pass "number" for your own number, or "issueDate" for a different invoice date. This can't be undone.

4. Email it

bash

curl -s -X POST "$API/invoices/$INVOICE/send" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "attachUbl": true }' | jq .status

Without to, the email goes to the customer's email address (and cc). You can pass to, cc, subject and message (placeholders like {number} work). See Sending by email.

5. Download the PDF and UBL

bash

curl -s "$API/invoices/$INVOICE/pdf?download=1" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" -o invoice.pdf
curl -s "$API/invoices/$INVOICE/ubl" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" -o invoice.xml

Marking as paid

Connect your own payment provider or bank: as soon as a payment comes in, mark the invoice.

bash

curl -s -X POST "$API/invoices/$INVOICE/mark-paid" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "paidAt": "2026-10-20" }' | jq .status

Finding an invoice by number, for example from the description of a bank payment:

bash

curl -s "$API/invoices?q=2026-0042&kind=invoice" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq '.data[] | {id, number, totalCents, displayStatus}'

Made a mistake? POST /invoices/{id}/mark-unpaid reverts it.

Reverse charge and EU customers

Pass vatTreatment (and for EU and foreign customers supplyType). The customer then needs a VAT number.

bash

curl -s -X POST "$API/invoices" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "customer": { "name": "Muster GmbH", "country": "DE", "vatNumber": "DE123456789",
                  "addressLine1": "Hauptstraße 5", "postalCode": "10115", "city": "Berlin" },
    "vatTreatment": "intra_eu",
    "supplyType": "services",
    "locale": "de",
    "lines": [ { "description": "Beratung", "quantity": "8", "unit": "HUR", "unitPriceCents": 9500 } ]
  }' | jq '{id, vatTreatment, vatTotalCents, totalCents}'

Values for vatTreatment: standard, reverse_charge, intra_eu, export, kor, exempt (with vatExemptionReason). See Choosing a VAT treatment.

Crediting

Credit the full invoice, as a draft:

bash

CREDIT=$(curl -s -X POST "$API/invoices/$INVOICE/credit-note" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq -r .id)

Partially: replace the lines (positive amounts) and issue it:

bash

curl -s -X PATCH "$API/invoices/$CREDIT" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "lines": [ { "description": "Web design discount", "quantity": "1", "unitPriceCents": 20000, "vatRate": "21" } ] }'

curl -s -X POST "$API/invoices/$CREDIT/issue" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" \
  -H "Content-Type: application/json" -d '{}' | jq .number

Crediting an invoice made outside EenFactuurMaken.nl: POST /invoices with "kind": "credit_note", "creditedInvoiceNumber" and "creditedInvoiceDate".

Reminders for overdue invoices

bash

for id in $(curl -s "$API/invoices?status=overdue&pageSize=100" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq -r '.data[].id'); do
  curl -s -X POST "$API/invoices/$id/remind" \
    -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq -r '"\(.number): \(.reminderCount) reminder(s)"'
done

With Pro, EenFactuurMaken.nl can also do this automatically.

VAT figures for your return

bash

curl -s "$API/stats?year=2026&quarter=3" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY" | jq .vat.selected

You get turnover and VAT per box (1a, 1b, 1c, 1e, 3a, 3b) plus exempt and KOR turnover. See VAT return.

Keeping track of changes

EenFactuurMaken.nl doesn't have webhooks (yet). To find out which invoices are new or paid, fetch the list periodically, newest first:

bash

curl -s "$API/invoices?sort=-createdAt&pageSize=50" \
  -H "Authorization: Bearer $EENFACTUURMAKEN_API_KEY"

Stay within the rate limits: once every few minutes is plenty.

Last updated on 13 October 2026

Stuck?

Email us at support@eenfactuurmaken.nl. Tell us what you tried and what happened, and we will help you out.

support@eenfactuurmaken.nl